341st CES needs help from housing residents identifying trees infested with mountain pine beetles

  • Published
  • By Jason Gibbons
  • 341st Civil Engineer Squadron Conservation Program Manager
MALMSTROM AIR FORCE BASE, Mont. --  How did a native insect get so out of control?

Mention the mountain pine beetle, and images of vast swaths of red and thoughts of wildfire probably cross your mind. Stories of frustration can often be overheard as folks retell of the sight of dead trees they saw crossing the mountain passes. It's no longer a few dots of red in a green landscape, but rather small islands of green in an ever-growing sea of red, pine beetle-infected trees. The impact to the Malmstrom community is only slight, compared to the National Forests, but the beetle is here and trees are failing.

Except for a few days during the summer when adults emerge, the mountain pine beetle spends its entire life under the bark of the infected tree. By June or early July, the pupae will have transformed into adults and within two days, will exit from the long feeding chambers of the phloem and inner bark layer of the tree. Unmated female beetles make the first attacks on new trees and release an aggregating pheromone that attracts other mountain pine beetles, until finally the mass attack overcomes the tree.

The beetles carry with them spores of blue-staining fungi that spread through the sapwood, stopping the flow of water and reducing the flow of pitch. The combination of beetle boring, feeding and fungi usually overwhelms and kills the tree.

Pitch is the principle defense against pine beetles and may successfully engulf and push out attacking adults. According to the U.S. Forest Service, evidence of successfully attacked trees includes boring dust around the base of the tree or pitch tubes containing reddish boring dust.

The spring following the attack, trees will fade to a yellowish color, then turn reddish-orange and eventually a familiar, frustrating red. Trees begin losing needles the second year after infection and the remaining needles drop at year three.

Looking around Malmstrom, it is evident there are trees here that appear to be in a similar state. Desiccation is a condition that is widespread on base and involves the removal of moisture, or drying of the tree due to wind and cold temperatures. It is commonly called winter desiccation and it causes the needles towards the tip of the branches to turn red while the needles closer to the trunk remain green and healthy.

Identifying mountain pine beetle infection is easier when one looks closely at the trunk of the tree. Although the pine beetle wreaks havoc statewide on pine species such as lodgepole, ponderosa, whitebark, limber and white pines, on Malmstrom, their tree of choice is the Scotch pine and there are very few left unaffected. Scotch pine can be readily identified by the orange, potato chip-like bark that transitions to an almost solid orange at the crown.

As you drive around Malmstrom, you will see orange ribbon around the trunks of many evergreen trees. As of early May, 36 conifers have been identified with mountain pine beetle and 46 others are dead or dying from various other causes; these trees may serve as general attractants for pine beetles this coming summer.

As the 341st CES works closely with grounds maintenance and pest shop personnel, the initial path forward will be to remove mountain pine beetle-infested trees and potential attractants by mid-June. Verbenone is a pheromone used by the mountain pine beetles to tell other beetles to look elsewhere - the tree is full. We will be placing commercial verbenone patches on trees that have been attacked but may have repelled the beetle, remaining healthy Scotch pine trees, and on other valuable trees based on their age and location.

This fall, the 341st CES will also apply for a Forest Health Protection grant through the U.S. Forest Service that has the potential to fund prevention, suppression and restoration efforts specifically on Malmstrom.

Do you have a sick or dead tree in your backyard that the 341st CES should be aware of? We'd like your help to find these trees so that we can address the problems. To report a tree or for more information about the forestry program on Malmstrom, please call 731-6333.